1. Field of the Invention
The present invention relates to devices for piercing a nut, and in particular, to devices having a manually operable cutter.
2. Description of Related Art
Before roasting certain nuts, such as chestnuts, the shell should be pierced to allow the escape of steam and to allow the meat of the nut to expand. Unless pierced, the nut has a tendency to explode, scattering and damaging the nut.
With this problem in mind, U.S. Pat. No. 2,700,994 proposed a plier-like device for piercing a chestnut. One Jaw of the device had crossed triangular blades arranged like a pyramid. A disadvantage with this device is that the chestnut tends to remain impaled on the blades, requiring manual removal. Also a plier-like device has the disadvantage that one hand must be dedicated to holding the pliers when repetitively piercing chestnuts. Thus, if two hands are needed during this procedure, the pliers must be laid aside and later fetched and reoriented before using. Furthermore, plier-like devices can be difficult to manipulate open and can demand much manual dexterity. In addition, such devices leave the piercing blades exposed, which presents a risk of personal injury.
Also, such devices lack a mechanism to hold the nut in place prior to the piercing operation. Also, such devices have no mechanism for limiting the depth of penetration of the blade, and can bore from one side of the nut to the other. To avoid excessive penetration the user must develop the judgement and feel for squeezing the plier-like device an appropriate amount for a particular size nut. Clearly, the difficulty in controlling such variability reduces the efficiency of these devices.
U.S. Pat. No. 5,052,107 shows a hinged device with two opposing Jaws. One jaw is annular for holding a chestnut, and the other jaw holds a blade to slit the chestnut. This device has similar disadvantages.
Other plier-like devices are known for opening a nut (as opposed to slitting). For example Australian Specification 232,827 shows a plier-like device having on one jaw a cup for holding a nut while the opposing jaw has a pointed and lobed device for cracking open the nut. Similarly, U.S. Pat. No. 3,048,208 shows another plier-like device in which one Jaw has a recess and the opposing Jaw a pair of crossed blades for cracking open a walnut. See also U.S. Pat. Nos. 1,710,629; 2,490,615; 2,804,111; 4,550,495; and 5,361,688, and DE-OS 3139052; FR 975,797; and UK 19,608.
Various tabletop devices are also known for cracking a nut. These have the advantage of being a unit that remains ready and lessens the need for the more complicated manipulations demanded by pliers. These known devices, however, are unconcerned with piercing a chestnut and do not suggest apparatus appropriate for such piercing. See U.S. Pat. Nos. 2,426,120; 4,200,042; 4,554,736; and 5,174,026.
In U.S. Pat. No. 3,924,326 a chestnut is prepared for roasting by slicing a segment from the nut as opposed to piercing the nut in the usual fashion.
U.S. Pat. No. 4,768,693 shows a table top, canister opener having four piercing blades and a shielding plate to prevent canister chards from flying about. This reference is unconcerned with piercing nuts.
Accordingly, there is a need for a convenient device for piercing a nut and that has one or more advantages, such as: automatically removal of the nut from the cutting blade, regulated penetration depth, protection from accidental cutting, or reduced manipulation during operation.